Heating rolls



March 20, 1956 WENNERLUND 2,739,218

HEATING ROLLS Filed May 20, 1953 INVENTOR. Ka -MM United States PatentHEATING ROLLS Eric Wenneriund, Ludvika, Sweden, assignor to The OhioBrass Company, Mansfield, (This) Appiication May 20, 1953, Serial No.356,261

13 Claims. (Cl. 219-37) My invention relates to that part only of anapparatus for forming laminated tubes of paper or other suitablematerial and has particular reference to laminated cores for condensertype bushings.

It is of extreme importance that condenser type cores shall be ofuniform structure and density throughout in order to meet the exactin"requirements of such a device and each core should be the equal of eachother core for uniformity of product.

Therefore, the apparatus upon which the core is produced must beabsolutely suited to meet the requirements. The core is normallyproduced on a set of rolls suitable for windin prepared paper or othersuitable material to form a uniform laminated body.

One of the most important elements of such a machine is the heating rollof which one or more is used to properly soften the insulating binder onthe material being wound, just prior to the paper web becoming a part ofthe core, the web being precoated with the binder.

One object of this invention is to provide heating rolls or cylinderswhich shall be uniformly heated and the temperature maintained, and thedegree of heat quite accurately controlled and varied by the operator tomeet the softening points of the different insulating binders used informing condenser type cores of laminated formation and uniform densitythroughout.

The roll is also suitable for use in machines for drying a Web, such asa web of damp paper or a paper web which is wet with printing.

In the treatment of certain materials with heated or hot rolls,difficulties often arise in obtaining an even heating over the entireroll. This is especially the case in winding machines for themanufacture of t cores by winding paper upon itself about an arbor orconductor red, the paper having been precoated with Babelite varnish orother suitable insulating adhesive. When the process concerns the rollon which the paper is wound, the paper will act as a heat insulation,and when it concerns the roll or rolls which are heated and bear againstthe paper as it winds, the latter will conduct the heat away from theroll. The consequence is that the ends of the roll are warmer than themiddle of it.

In order to obtain an even temperature all over the surface of suchtells, it has earlier been the practice to heat them by steam, hot oilor other medium in gas or liquid form which is caused to circulatethrough the rolls by means of pumps. This method, by itself excellent,has, however, the great disadvantage that it is difiicult, especially athigh temperatures to secure and maintain tight joints between the pipefeeding the heating medium to the roll and the rotating roll.

The present invention concerns an arrangement by which this disadvantageis completely avoided and according to the invention this is obtained byproviding the heating roll with one or more confined spaces, partlyfilled with a medium which is liquid, at least when hot ice and whichdistributes the heat evenly throughout the heating roll as it rotates.

The means for heating the liquid within the roll is stationary andindependent of the roll proper so that the roll rotates relative to theheating means with no physical connection whatsoever with the heatingmeans.

The roll may for instance consist of two concentric cylinders closelyjoined with each other at their ends by ring shaped covers whereby thespace or receptacle between the cylinders may be kept sufiicientlyfilled with a liquid having a suitable boiling-point.

The cylinder may also be constructed solid but provided with a pluralityof individual channels which extend from one end of the cylinder to theother and which may each be closed by end caps. The last'mentionedarrangement can be of advantage if the heating rolls each have a smalldiameter.

As the transmission of heat inside the cylinder chiefly takes place byevaporation and condensation of the liquid according to the principle ofthe cold wall in order to get the greatest heat-transmission at certaintemperature, it is important that the space in the cylinder is free asmuch as possible from permanent gases. If, for instance, Water is used,the air dissolved in it should be liberated before the space in the rollis definitely closed.

In the drawing- Fig. l is a vertical section through the longitudinalaxis of a roll.

Fig. 2 is a full transverse section of a roll according to Fig. 1.

Fig. 3 is a vertical section through the longitudinal axis of anotherroll.

Fig. 4 is a full transverse section of the roll according to Fig. 3.

Fig. 5 discloses a means of supporting an electric heating elementindependent of the cylindrical portion of the roll.

Fig. 6 discloses means for supporting a dilferent form of electricheating element thanthat of Fig. 5.

Fig. l of the drawing shows an embodiment of a roll in which 1 signifiesthe outer cylinder and 2 the inner cylinder. The two cylinders arejoined with each other by ring shaped end plates 6, welded at the endsof the cylinder as indicated at w. The single space or chamber 4 betweenthe cylinders contains a liquid 4' which has a suitable boiling-pointand the whole roll is heated by an electric heating element 5 placed inthe center or here 9 of the roll. Journals 7 project from eachend of theroll and 3 designates a paper web in contact with the roll.

Fig. 3 shows an arrangement of a roll consisting of a cylinder 8provided with a central bore 11 in which the heating arrangement 5 isplaced. The cylinder is provided with several channels 10 situatedconcentrically around the central bore 11. These channels are closed atthe ends with ring shaped plates 12 Welded to the roll, and the channelsmay be connected with one another by one or both circular grooves 13which are formed in the ends of the roll or inner face of the plates 12.The channels it) are partly filled with a medium 4' which is liquid whenhot. The channels may each be either independent of each other as byomitting the grooves 13, the preferred construction is shown in Fig. 3,and forming in eifect the single recess, by which construction a moreeffective heating is obtained and thus also a more uniform temperaturesecured throughout the roll.

Fig. 5 shows a portion of one end of the heating element 5 and themanner in which it may be supported independent of the roll by thestandard 25 and heat resisting insulation 26.

The electric heating element 5' shown in Fig. 6 is a single type elementsupported at each and beyond the ends of the journals 7 by the standards25 and heat resisting insulation 26.

In order to maintain the temperature of the rolls uniform through outthe operation of forming the cores, it is essential to provide means toregulate the temperature by controlling the heating of element 5. Thismay be accomplished in various ways, two of which are disclosed in Figs.1 and 3. V

In Fig. 1 a control board 20 is provided on which is mounted an ammeter21, a rheostat22 and a switch 23, under control of the operator, who bywatching the operation of the winding machine, can manipulate therheostat accordingly. The heater and the several devices are connectedto a source of electric current by means of conductors 16 and 17.

In Fig. 3 is a modification thereof in that a thermal switch 24 isintroduced in the control circuit 17 which maintains a constanttemperature of the roll by automatically open- .ing and closing thecircuit as the temperature of the roll requires. The thermal switch 24may be of any suitable type maintained in contact with the rotating rollbut stationary relative thereto.

Having described the heating roll according to my invention, it will benoted that the heating medium is contained in air tight chambers 4 andchambers 10. Each roll (Figs. 1 and 3) is provided with a suitable meansfor fillingand emptying the cylinders controlled by one or more plugs30.

After the heating medium, say water, has been placed in the cylinder andthe heating element 5 operated to heat the water to the steaming stageto drive out the air from the cylinder, the cylinder is closed byreplacing the plug 30.

The rolls are used in a horizontal position in the winding machine androtate about a horizontal axis; the outer surface of the heated roll isengaged by the web as it moves across the same. a

The roll of Figs. 1 and 3 is only partially filled with th heatingliquid in order to allow space for expansion when heated. The liquidfiller, however, extends above the longitudinal axis of the roll.

A pipe with spaces opening along its length may be substituted for theelectric element 5 or 5' and the pipe connected to a source of gassupply, as a means of heating the roll and liquid medium.

The resistance element 5 or 5 may be of carbon or of a suitable highresistance metal.

What I claim as new and desire to protect by Letters Patent of theUnited States is set forth in the following claims.

I claim:

1. A hot cylinder for use in a machine for uniformly winding a web ofprepared material onto a metal arbor comprising, an elongated rotatablecylindrical member, the inner wall of the cylindrical member forming anopen end tubular bore extending axially throughout the length of thecylindrical member, the cylindrical member recessed between the wall ofthe bore and the outer wall of the cylindrical member for the length ofthe member, the recess and the bore being non-communicating, stationaryheating means positioned in the bore independent of the wall andremovable through an end opening of the bore, the heating meansextending substantially the length of the bore whereby the inner wall ofthe cylindrical member will be uniformly heated, means by which theheating means may be brought to the required temperature, means closingeach end of the recess means, a fluid heating element contained in thesaid recess to uniformly distribute the heat throughout the cylindricalmember, and means at each end of the cylindrical member to support thecylindrical member in a horizontal and rotatable relation independent ofthe heating means.

2. A hot roll according to claim 1 characterized by the heating elementbeing liquid at the working temperature of the cylindrical member andhaving a suitable boiling point, whereby the heat of the cylindricalmember is uniformly distributed throughout its length.

3. A hot roll for a winding machine constructed according to claim 1,characterized in that the heating means within the bore also comprisesmeans for electrically connecting the heating means to a source ofelectric current, and thermal control means associated with the roll andwith the connecting means to open close the connecting means, wherebythe temperature of the roll is automatically maintained as required.

4. A hot roll for a winding machine comprising, an elongated cylinder, asecond elongated cylinder of less diameter than that of the firstcylinder, the cylinders of substantially the same length and thecylinders mounted in concentric relation, means closing the ends of thespace between the concentric cylinders thereby forming a closedreceptacle with a hollow interior for holding a liquid heat distributingmedium, means extending from each end of the roll to support the roll inhorizontal rotative relation with the other parts of the windingmechanism, heating means positioned within the second cylinder and fixedsupport means for the heating means at each end of the roll so that theroll rotates about the heating means.

5. A hot roll according to claim 4 in which the heating means comprisesan electric element subject to heating by an electric current, andcontrolled means to connect the element to a source of electric current.

6. A hot roll for a winding machine comprising, a pair of elongatedconcentric cylinders of such relative diameter as to provide a spacetherebetween for the length of the cylinders, a plate at each end of thesaid space between the cylinders and secured thereto to seal the spaceand form a closed recess between the cylinders and hold the cylindersfor holding a heat distributing medium in spaced relation, means at eachend of the roll to support the same in rotative relation to the windingmechanism, and fixed electrical heating means positioned in the bore ofthe inner cylinder and extending substantially the length of the rollwhereby the inner cylinder is uniformly heated throughout its length.

7. A hot roll as set forth in claim 6 characterized by the electricalheating means connected to a source of electric current, control meansassociated with the electric circuit for regulating the temperature ofthe inner roll.

8. A hot roll as set forth in claim 6 characterized by the recessbetween the cylinders provided with a heating medium that partiallyfills the said recess and is liquid at the working temperature of theroll whereby the temperature of the inner cylinder is uniformlytransmitted to the outer cylinder. 7

9. A hot roll as set forth in claim 8 in that the electrical heatingmeans is electrically connected to a source of electric current andmeans associated with the electric circuit for controlling thetemperature of the heating means whereby the temperature of the heatingmedium in the said recess may be controlled.

10. A hot roll for a winding machine comprising, an elongated outercylindrical member with a central cylindrical member provided with abore extending the length of the cylindrical member, the outercylindrical member provided with a plurality of spaced parallellongitudinal channels positioned between the outer surfaces of thecylindrical members and terminating at the ends of the outer cylindricalmember, means closing the ends of the space between the cylindricalmembers beyond the ends of the channels to interconnect the channels atthe ends thereof whereby the said channels form closed recess meanssurrounding the said central cylindrical member ing the outer contactsurface of the cylindrical member to the required temperature as thecylinder turns about the heating means.

11. The invention in accordance with claim 8 and including thermalcontrol means connected to the electrical heating means and responsiveto the temperature of the outer one of the eccentric cylinders forregulating the temperature of the heating means.

12. A roll for a winding machine comprising a hollow outer cylindricalmember, an inner cylindrical member concentrically disposed within theouter member having the ends thereof projecting beyond ends of the outermember to provide bearing means on which the roll may be turned, a plateat each end of the outer cylindrical member, each joined to the outercylindrical member and to the inner cylindrical member about theperipheries thereof to form a closed interior space adapted to hold aheat distributing medium and a longitudinal bore axially through theinner member for accommodating a stationary heating means about whichthe roll may be rotated.

13. The invention in accordance with claim 12 including longitudinalchannel forming means disposed within the space between the said innerand outer cylindrical members, said channel forming means being spacedfrom the end plates to form passages through which the heat distributingmedium can circulate between the channels.

References Cited in the file of this patent UNITED STATES PATENTS963,942 Richardson July 12, 1910 1,037,573 Allen Sept. 3, 1912 1,168,171Crumbaugh Jan. 11, 1916 1,268,990 Moeller June 11, 1918 1,587,963 KnopfJune 8, 1926 1,819,534 Akerlow Aug. 18, 1931 2,131,336 Sullivan Sept.27, 1938 2,474,759 Schmitz June 28, 1949

